1. Field of the Invention
The present invention relates to an image inspection apparatus in a plate making process for inspecting two images which are formed in different stages of the plate making process by comparing the same with each other, and an image inspection method in the plate making process.
2. Description of the Background Art
In a plate making process, an original plate film F1 (consisting of F1Y, F1M, F1C and F1K) is formed in response to a previously specified print content for performing exposure/development thereby forming a press plate P1 (consisting of P1Y, P1M, P1C and P1K) as shown in FIG. 55, as well known in the art. In order to inspect whether or not a printed matter obtained from the press plate 1P formed in the aforementioned manner matches with the specified print content, a trial print, i.e., a proof sheet (first revise) PS1 is prepared from the press plate P1, and compared with the specified print content. If a portion mismatching with the specified print content is found in this stage, the operation returns to the plate making process for forming a new original plate film F2 (consisting of F2Y, F2M, F2C and F2K) and a new press plate P2 (consisting of P2Y, P2M, P2C and P2K), so that a new proof sheet (second revise) PS2 is prepared from the press plate P2. If further correction is necessary, a corrected original plate film F3 (consisting of F3Y, F3M, F3C and F3K) is employed for performing exposure/development thereby forming a further press plate P3 (consisting of P3Y, P3M, P3C and P3K) similarly to the above, so that a proof sheet (third revise) PS3 is prepared from this press plate P3.
Such correction requires a complicated manual operation, leading to improper correction of a portion mismatching with the specified print content and requiring correction or erroneous correction of another portion requiring no correction.
To this end, a number of apparatuses for inspecting such erroneous correction have been proposed in general. For example, Japanese Patent Laid Open Gazette No. 5-281697 (1993) or 7-271009 (1995) describes an apparatus which reads images of an original plate film formed first and a corrected original plate film and compares these images with each other for detecting match/mismatch, so that an operator can decide (inspect) whether or not the corrected content is proper.
In general, a conventional apparatus such as that described in Japanese Patent Laid Open Gazette No. 5-281697 regards uncorrected and corrected original plate films as a reference and an object respectively and compares these reference and target with each other. In practice, however, an actual print is obtained through steps of exposure/development, proof reading and printing after formation of the original plate films, and hence erroneous exposure in the exposure step or erroneous printing in the proof reading or printing step cannot be inspected by merely inspecting the original plate films.